Spot-welding apparatus



F. THORNTON, JR.

SPOT WELDING APPARATUS.

APPLICATION FILED APR. 18. 1919.

1,327,792. Patented Jan. 13,1920.

INVENTOR Fly 3. flan/r Thor/172m, Jr:

WITNESSES:

UNIT D.

FRANK THORNTON, JR., OF MANSFIELD, OHIO, ASSIGNORTO WESTINGHOUSEELECTRIC 8; MANUFACTURING- COMPANY, A CORPORATION OF PENNSYLVANIA.

SPOT-WELDING APPARATUS.

Application filed April 18, 1919.

To all whom it may concern:

Be it known that I, FRANK THORNTON, Jr., a citizen of the United States,and I a resident of Mansfield, in the county of Richland and Stateof'Ohio, have invented a new and useful Improvement in Spot-WeldingApparatus, of which the following is a specification.

My invention relates to apparatus for.

spot welding and it has, for its primary object, the provision ofapparatus of the above designated character which shall be relativelylight in weight and compact of structure.

Another object of my invention is to provide spot-welding apparatuswhich shall permit of the employment of electric current to obtain boththe necessary compressive force upon the objects being welded .and theheating effect to fuse the objects at the point where it is desired tounite them.

A still further object of my invention is to provide spot-weldingapparatus which may be adjusted by skilled workmen and thereafteroperated, with a high degree of efficiency, by unskilled workmen.

With these and other objects in view, my invention will be more fullydescribed, illustrated in the drawings, in the several views of whichcorresponding numerals indicate lik parts, and then particularly pointedout in the claims.

In the drawings, Figure 1 is a diagrammatic view of spot-weldingapparatus and electric control circuits therefor which embody myinvention; Fig. 2 is a side View, on a larger scale, of a switchmechanism employed in the apparatus shown in Fig. 1, and Fig. 3 is asectional view taken substantially along the line IIIII'I of Fig. 2.

In practising my invention, I may employ apparatus, suchas shown in Fig.1, which comprises a base member 1 upon which may be secured, by anysuitable means, such as nuts and bolts 2, a plurality of supportingmembers 3 and 4, the supporting members being preferably insulated fromeach other,

- as indicated at 5. The member 3 may be provided, at one end, with aremovable clamping member 6 adapted to secure an electrode member 7 toth member 3. The other supporting member 4 ay be provided withsubstantially parallel arms 8 so spaced as to permit of supporting anelectrical coil '9 upon the lower arm. The electric coil 9 Specificationof Letters Patent.

Patented Jan.13, ieao.

Serial no. 290,941.

. is preferably formed with a somewhat restricted portion 11 at itslower end which may function as an electrode and may also have anotherrestricted portion 12 at its other 'end. The armature 10 may bepositioned within the coil 9 by disposing the electrode 11 in a suitableopening provided in the lower arm 8, and the restricted portion 12 maybe extended through a similar alined opening in the upper arm 8, thearmature being held in its uppermost position by a spring 13 surroundingthe end portion 12 and secured in such position by a nut 14-.

A switch mechanism 15, which may be operated by the coil 9, by means ofits armature 10, comprises a lever 16, carrying a switch blade. 16, atone end, and may be connected, at its other end, to the upper end of theportion 12 of the armature 10 and may be insulated therefrom. The lever16 may be pivoted, as indicated at 17, and may be connected to aretarding device 18. A. suitably supported resilient contact member 19is adapted to cooperate with the switch blade 16.

The switch mechanism 15is best shown in Figs. 1 and 2. The switch blade16 may comprise a metallic plate 20 and a hon-con ducting plate 21 andmay be mounted upon the lever 16 at an angle thereto. Electrical contactis made between resilient member 19 v The coil 9 may be connected across"supply mains 22 byleads 28 and 24 which may be provided with asuit-ableswitch 25 for opening and closing the circuit of the coil 9.The amount of energy supplied to the coil 9 from the mains 22 may beregulated by a suitable rheostat 26. The switch blade 16 and member 19of the switch mechanism may be connected in parallel with the coil 9 bya lead 27 which may be connected to the member 16 and to one side of thecircuit, as indicated at 29, and by a lead 28 whichmay be connected tothe member .19 through a coil 30 of a relay switch 31 and to the otherside of the coil circuit, as indicated at the junction point 31.

A heating clrcuit may be provided by employing a transformer 32 having aprimary winding 33, provided with voltage-control taps, which may beautomatically connected in series with the supply mains 22 by the relayswitch 31 through contacts 34:, 35, 36

and 37. A secondary winding 38 of the transformer 32 may be connected,at one side, to the supporting member 4: and at the other, to thesupporting member 3,1in any suitable manner. A secondary circuit is thusprovided which includes the electrode members 7 and 11, the electrodemember 11 being connected to the supporting member 4 by a flexible lead39.

lln welding a plurality of metallic members together, the members may bedisposed upon the stationary electrode member 7, and the circuit beclosed, through the switch 25, to energize the coil 9, the degree ofenergy being regulated by the rheostat 26. When the coil 9 is energized,the armature is drawn 1 into the coil, thus compressing the spring 13and causing the electrode 11 to compressively engage the members to bewelded.

,The lever 16 is actuated by the movement of the armature 10 to causethe switch blade 16 to engage the resilient member 19. As

' before stated, electrical contact is made upon the up-stroke of'theswitch blade 16', thereby closing a circuit through the coil 30 of therelay switch 31 which, therefore, automatically connects the primarywinding 33 of the transformer 32 to the supply mains 22. In accordancewith the well known transformer action, an electromotive force isinduced in the secondary winding 38 of the transformer which causes acurrent to.

flow through the electrodes 7 and 11 and the interposed work whichcooperate to form a closed circuit.- c

The metalliemembers engaged by the electrodes are heated, on account ofcontact re- 1 sistance, and theheated metal is united by thecompressive-force produced by the .electrodes. The degree of compressionmay be regulated, if desired, by adjusting the rheostat 26 whichcontrols the energy supplied to the coil 9. Furthermore, the length oftime to which the members being welded are subjected to the heatingeffect of the current from the transformer may be varied by adjustingthe retarding device 18 of the switch mechanism 15. The welding currentis supplied while the switch blade 16 is in contact wlth the resilientmember 19 on its up-stroke, the circuit being broken when the switchblade 16 passes the resilient member 19. 1 The lever arm 16 is held inits upper position until the circuit energizing the to. the electriccoil 9 may then -magnetic means for forcing electric coil ada coil 9 isbroken, the spring 13 being then permitted to raise the armature 10 andconse quently to lower the lever arm 16.

Although I have described apparatus that is adapted for spot welding, itis obvious that minor changes may be made i-n'the construction thereofand in the electric control therefor, and l desire that no limitationsshall be imposed except such as are indicated in the appended claims.

I claim as my invention:

1. A spot-Welding apparatus comprising. a plurality of electrodemembers, electromagnetic means for forcing the members into engagementwith interposed work, and an automatically actuated circuit-closer forclosing a'heating circuit including the electrode members. I

V 2. A spot-welding apparatus comprising a plurality ofelectrodemembers, electromagnetic means for forcing the members intoengagement with interposed work, means for automatically connecting theelectrode members in a heating circuit, and means for automaticallydisconnecting the electrode membersfrom the heating circuit.

3. A spot-welding apparatus comprising a plurality of electrode members,electrothe members into engagement with lHlZ'Z-BIdPOSP/d work,

means for automatically conne ting the electrode members in a heatingcircuit, and.

means for automatically disconnecting the eledtrode members from theheating circuit at a predetermined time.

4. A spot-welding apparatus comprising ,a stationary and a movableelectrode, an

electric coil adapted to force the movable electrode toward thelstationary electrode when it is energized, means for automaticallyconnecting the electrodes in a heating circuit, and means forautomatically disconnecting the electrodes from the heating circuit at apredetermined time.

7 5. A spot-welding apparatus comprising a stationary and a movableelectrode, an v ted to force the movable electrode towar the, stationaryelectrode when it is energized, :rneans for varying the energy suppliedto the coil, means tending to maintain the electrodes in. spacedrelation,

means for automatically connecting the electrodes in a heating circuit,and means for automatically disconnecting the electrodes from thecircuit at a predetermined time.-

In testimony whereof'I have hereunto subscribed my name this 31st day ofMarch,

- FRANK THORNTON, JR.

